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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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SPDX-License-Identifier: GPL-2.0/* * Common code for probe-based Dynamic events. * * This code was copied from kernel/trace/trace_kprobe.c written by * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> * * Updates to make this generic: * Copyright (C) IBM Corporation, 2010-2011 * Author: Srikar Dronamraju */#define pr_fmt(fmt) "trace_probe: " fmt
#include <linux/bpf.h>#include <linux/fs.h>
#include "trace_btf.h"#include "trace_probe.h"
#undef C#define C(a, b) b
static const char *trace_probe_err_text[] = { ERRORS };
static const char *reserved_field_names[] = { "common_type", "common_flags", "common_preempt_count", "common_pid", "common_tgid", FIELD_STRING_IP, FIELD_STRING_RETIP, FIELD_STRING_FUNC,};
/* Printing in basic type function template */#define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\{ \ trace_seq_printf(s, fmt, *(type *)data); \ return !trace_seq_has_overflowed(s); \} \const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u")DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d")DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x")DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent){ trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data); return !trace_seq_has_overflowed(s);}const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
/* Print type function for string type */int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent){ int len = *(u32 *)data >> 16;
if (!len) trace_seq_puts(s, FAULT_STRING); else trace_seq_printf(s, "\"%s\"", (const char *)get_loc_data(data, ent)); return !trace_seq_has_overflowed(s);}
const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
/* Fetch type information table */static const struct fetch_type probe_fetch_types[] = { /* Special types */ __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1, "__data_loc char[]"), __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1, "__data_loc char[]"), __ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1, "__data_loc char[]"), /* Basic types */ ASSIGN_FETCH_TYPE(u8, u8, 0), ASSIGN_FETCH_TYPE(u16, u16, 0), ASSIGN_FETCH_TYPE(u32, u32, 0), ASSIGN_FETCH_TYPE(u64, u64, 0), ASSIGN_FETCH_TYPE(s8, u8, 1), ASSIGN_FETCH_TYPE(s16, u16, 1), ASSIGN_FETCH_TYPE(s32, u32, 1), ASSIGN_FETCH_TYPE(s64, u64, 1), ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0), ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0), ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0), ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0), ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8, 0), ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
ASSIGN_FETCH_TYPE_END};
static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags){ int i;
/* Reject the symbol/symstr for uprobes */ if (type && (flags & TPARG_FL_USER) && (!strcmp(type, "symbol") || !strcmp(type, "symstr"))) return NULL;
if (!type) type = DEFAULT_FETCH_TYPE_STR;
/* Special case: bitfield */ if (*type == 'b') { unsigned long bs;
type = strchr(type, '/'); if (!type) goto fail;
type++; if (kstrtoul(type, 0, &bs)) goto fail;
switch (bs) { case 8: return find_fetch_type("u8", flags); case 16: return find_fetch_type("u16", flags); case 32: return find_fetch_type("u32", flags); case 64: return find_fetch_type("u64", flags); default: goto fail; } }
for (i = 0; probe_fetch_types[i].name; i++) { if (strcmp(type, probe_fetch_types[i].name) == 0) return &probe_fetch_types[i]; }
fail: return NULL;}
static struct trace_probe_log trace_probe_log;extern struct mutex dyn_event_ops_mutex;
const char *trace_probe_log_init(const char *subsystem, int argc, const char **argv){ lockdep_assert_held(&dyn_event_ops_mutex);
trace_probe_log.subsystem = subsystem; trace_probe_log.argc = argc; trace_probe_log.argv = argv; trace_probe_log.index = 0; return subsystem;}
void trace_probe_log_clear(void){ lockdep_assert_held(&dyn_event_ops_mutex);
memset(&trace_probe_log, 0, sizeof(trace_probe_log));}
void trace_probe_log_set_index(int index){ lockdep_assert_held(&dyn_event_ops_mutex);
trace_probe_log.index = index;}
void __trace_probe_log_err(int offset, int err_type){ char *command, *p; int i, len = 0, pos = 0;
lockdep_assert_held(&dyn_event_ops_mutex);
if (!trace_probe_log.argv || !trace_probe_log.argc) return;
/* Recalculate the length and allocate buffer */ for (i = 0; i < trace_probe_log.argc; i++) { if (i == trace_probe_log.index) pos = len; len += strlen(trace_probe_log.argv[i]) + 1; } command = kzalloc(len, GFP_KERNEL); if (!command) return;
if (trace_probe_log.index >= trace_probe_log.argc) { /** * Set the error position is next to the last arg + space. * Note that len includes the terminal null and the cursor * appears at pos + 1. */ pos = len; offset = 0; }
/* And make a command string from argv array */ p = command; for (i = 0; i < trace_probe_log.argc; i++) { len = strlen(trace_probe_log.argv[i]); memcpy(p, trace_probe_log.argv[i], len); p[len] = ' '; p += len + 1; } *(p - 1) = '\0';
tracing_log_err(NULL, trace_probe_log.subsystem, command, trace_probe_err_text, err_type, pos + offset);
kfree(command);}
/* Split symbol and offset. */int traceprobe_split_symbol_offset(char *symbol, long *offset){ char *tmp; int ret;
if (!offset) return -EINVAL;
tmp = strpbrk(symbol, "+-"); if (tmp) { ret = kstrtol(tmp, 0, offset); if (ret) return ret; *tmp = '\0'; } else *offset = 0;
return 0;}
/** * traceprobe_parse_event_name() - Parse a string into group and event names * @pevent: A pointer to the string to be parsed. * @pgroup: A pointer to the group name. * @buf: A buffer to store the parsed group name. * @offset: The offset of the string in the original user command, for logging. * * This parses a string with the format `[GROUP/][EVENT]` or `[GROUP.][EVENT]` * (either GROUP or EVENT or both must be specified). * Since the parsed group name is stored in @buf, the caller must ensure @buf * is at least MAX_EVENT_NAME_LEN bytes. * * Return: 0 on success, or -EINVAL on failure. * * If success, *@pevent is updated to point to the event name part of the * original string, or NULL if there is no event name. * Also, *@pgroup is updated to point to the parsed group which is stored * in @buf, or NULL if there is no group name. */int traceprobe_parse_event_name(const char **pevent, const char **pgroup, char *buf, int offset){ const char *slash, *event = *pevent; int len;
slash = strchr(event, '/'); if (!slash) slash = strchr(event, '.');
if (slash) { if (slash == event) { trace_probe_log_err(offset, NO_GROUP_NAME); return -EINVAL; } if (slash - event + 1 > MAX_EVENT_NAME_LEN) { trace_probe_log_err(offset, GROUP_TOO_LONG); return -EINVAL; } strscpy(buf, event, slash - event + 1); if (!is_good_system_name(buf)) { trace_probe_log_err(offset, BAD_GROUP_NAME); return -EINVAL; } *pgroup = buf; *pevent = slash + 1; offset += slash - event + 1; event = *pevent; } len = strlen(event); if (len == 0) { if (slash) { *pevent = NULL; return 0; } trace_probe_log_err(offset, NO_EVENT_NAME); return -EINVAL; } else if (len >= MAX_EVENT_NAME_LEN) { trace_probe_log_err(offset, EVENT_TOO_LONG); return -EINVAL; } if (!is_good_name(event)) { trace_probe_log_err(offset, BAD_EVENT_NAME); return -EINVAL; } return 0;}
static int parse_trace_event_arg(char *arg, struct fetch_insn *code, struct traceprobe_parse_context *ctx){ struct ftrace_event_field *field; struct list_head *head;
head = trace_get_fields(ctx->event); list_for_each_entry(field, head, link) { if (!strcmp(arg, field->name)) { code->op = FETCH_OP_TP_ARG; code->data = field; return 0; } } return -ENOENT;}
static int parse_trace_event(char *arg, struct fetch_insn *code, struct traceprobe_parse_context *ctx){ int ret;
if (code->data) return -EFAULT; ret = parse_trace_event_arg(arg, code, ctx); if (!ret) return 0; return -EINVAL;}
#ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
static u32 btf_type_int(const struct btf_type *t){ return *(u32 *)(t + 1);}
static bool btf_type_is_char_ptr(struct btf *btf, const struct btf_type *type){ const struct btf_type *real_type; u32 intdata; s32 tid;
real_type = btf_type_skip_modifiers(btf, type->type, &tid); if (!real_type) return false;
if (BTF_INFO_KIND(real_type->info) != BTF_KIND_INT) return false;
intdata = btf_type_int(real_type); return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) && BTF_INT_BITS(intdata) == 8;}
static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type){ const struct btf_type *real_type; const struct btf_array *array; u32 intdata; s32 tid;
if (BTF_INFO_KIND(type->info) != BTF_KIND_ARRAY) return false;
array = (const struct btf_array *)(type + 1);
real_type = btf_type_skip_modifiers(btf, array->type, &tid);
intdata = btf_type_int(real_type); return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) && BTF_INT_BITS(intdata) == 8;}
static struct btf *ctx_btf(struct traceprobe_parse_context *ctx){ return ctx->struct_btf ? : ctx->btf;}
static int check_prepare_btf_string_fetch(char *typename, struct fetch_insn **pcode, struct traceprobe_parse_context *ctx){ struct btf *btf = ctx_btf(ctx);
if (!btf || !ctx->last_type) return 0;
/* char [] does not need any change. */ if (btf_type_is_char_array(btf, ctx->last_type)) return 0;
/* char * requires dereference the pointer. */ if (btf_type_is_char_ptr(btf, ctx->last_type)) { struct fetch_insn *code = *pcode + 1;
if (code->op == FETCH_OP_END) { trace_probe_log_err(ctx->offset, TOO_MANY_OPS); return -E2BIG; } if (typename[0] == 'u') code->op = FETCH_OP_UDEREF; else code->op = FETCH_OP_DEREF; code->offset = 0; *pcode = code; return 0; } /* Other types are not available for string */ trace_probe_log_err(ctx->offset, BAD_TYPE4STR); return -EINVAL;}
static const char *fetch_type_from_btf_type(struct btf *btf, const struct btf_type *type, struct traceprobe_parse_context *ctx){ u32 intdata;
/* TODO: const char * could be converted as a string */ switch (BTF_INFO_KIND(type->info)) { case BTF_KIND_ENUM: /* enum is "int", so convert to "s32" */ return "s32"; case BTF_KIND_ENUM64: return "s64"; case BTF_KIND_PTR: /* pointer will be converted to "x??" */ if (IS_ENABLED(CONFIG_64BIT)) return "x64"; else return "x32"; case BTF_KIND_INT: intdata = btf_type_int(type); if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) { switch (BTF_INT_BITS(intdata)) { case 8: return "s8"; case 16: return "s16"; case 32: return "s32"; case 64: return "s64"; } } else { /* unsigned */ switch (BTF_INT_BITS(intdata)) { case 8: return "u8"; case 16: return "u16"; case 32: return "u32"; case 64: return "u64"; } /* bitfield, size is encoded in the type */ ctx->last_bitsize = BTF_INT_BITS(intdata); ctx->last_bitoffs += BTF_INT_OFFSET(intdata); return "u64"; } } /* TODO: support other types */
return NULL;}
static int query_btf_context(struct traceprobe_parse_context *ctx){ const struct btf_param *param; const struct btf_type *type; struct btf *btf; s32 nr;
if (ctx->btf) return 0;
if (!ctx->funcname) return -EINVAL;
type = btf_find_func_proto(ctx->funcname, &btf); if (!type) return -ENOENT;
ctx->btf = btf; ctx->proto = type;
/* ctx->params is optional, since func(void) will not have params. */ nr = 0; param = btf_get_func_param(type, &nr); if (!IS_ERR_OR_NULL(param)) { /* Hide the first 'data' argument of tracepoint */ if (ctx->flags & TPARG_FL_TPOINT) { nr--; param++; } }
if (nr > 0) { ctx->nr_params = nr; ctx->params = param; } else { ctx->nr_params = 0; ctx->params = NULL; }
return 0;}
static void clear_struct_btf(struct traceprobe_parse_context *ctx){ if (ctx->struct_btf) { btf_put(ctx->struct_btf); ctx->struct_btf = NULL; ctx->last_struct = NULL; }}
static void clear_btf_context(struct traceprobe_parse_context *ctx){ if (ctx->btf) { btf_put(ctx->btf); ctx->btf = NULL; ctx->proto = NULL; ctx->params = NULL; ctx->nr_params = 0; }}
/* Return 1 if the field separator is arrow operator ('->') */static int split_next_field(char *varname, char **next_field, struct traceprobe_parse_context *ctx){ char *field; int ret = 0;
field = strpbrk(varname, ".-"); if (field) { if (field[0] == '-' && field[1] == '>') { field[0] = '\0'; field += 2; ret = 1; } else if (field[0] == '.') { field[0] = '\0'; field += 1; } else { trace_probe_log_err(ctx->offset + field - varname, BAD_HYPHEN); return -EINVAL; } *next_field = field; }
return ret;}
/* * Parse the field of data structure. The @type must be a pointer type * pointing the target data structure type. */static int parse_btf_field(char *fieldname, const struct btf_type *type, struct fetch_insn **pcode, struct fetch_insn *end, struct traceprobe_parse_context *ctx){ struct fetch_insn *code = *pcode; const struct btf_member *field; u32 bitoffs, anon_offs; bool is_struct = ctx->struct_btf != NULL; struct btf *btf = ctx_btf(ctx); char *next; int is_ptr; s32 tid;
do { if (!is_struct) { /* Outer loop for solving arrow operator ('->') */ if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) { trace_probe_log_err(ctx->offset, NO_PTR_STRCT); return -EINVAL; }
/* Convert a struct pointer type to a struct type */ type = btf_type_skip_modifiers(btf, type->type, &tid); if (!type) { trace_probe_log_err(ctx->offset, BAD_BTF_TID); return -EINVAL; } } /* Only the first type can skip being a pointer */ is_struct = false;
bitoffs = 0; do { /* Inner loop for solving dot operator ('.') */ next = NULL; is_ptr = split_next_field(fieldname, &next, ctx); if (is_ptr < 0) return is_ptr;
anon_offs = 0; field = btf_find_struct_member(btf, type, fieldname, &anon_offs); if (IS_ERR(field)) { trace_probe_log_err(ctx->offset, BAD_BTF_TID); return PTR_ERR(field); } if (!field) { trace_probe_log_err(ctx->offset, NO_BTF_FIELD); return -ENOENT; } /* Add anonymous structure/union offset */ bitoffs += anon_offs;
/* Accumulate the bit-offsets of the dot-connected fields */ if (btf_type_kflag(type)) { bitoffs += BTF_MEMBER_BIT_OFFSET(field->offset); ctx->last_bitsize = BTF_MEMBER_BITFIELD_SIZE(field->offset); } else { bitoffs += field->offset; ctx->last_bitsize = 0; }
type = btf_type_skip_modifiers(btf, field->type, &tid); if (!type) { trace_probe_log_err(ctx->offset, BAD_BTF_TID); return -EINVAL; }
ctx->offset += next - fieldname; fieldname = next; } while (!is_ptr && fieldname);
if (++code == end) { trace_probe_log_err(ctx->offset, TOO_MANY_OPS); return -EINVAL; } code->op = FETCH_OP_DEREF; /* TODO: user deref support */ code->offset = bitoffs / 8; *pcode = code;
ctx->last_bitoffs = bitoffs % 8; ctx->last_type = type; } while (fieldname);
return 0;}
static int __store_entry_arg(struct trace_probe *tp, int argnum);
static int parse_btf_arg(char *varname, struct fetch_insn **pcode, struct fetch_insn *end, struct traceprobe_parse_context *ctx){ struct fetch_insn *code = *pcode; const struct btf_param *params; const struct btf_type *type; char *field = NULL; int i, is_ptr, ret; u32 tid;
if (!ctx->funcname && !(ctx->flags & TPARG_FL_TEVENT)) return -EINVAL;
is_ptr = split_next_field(varname, &field, ctx); if (is_ptr < 0) return is_ptr; if (!is_ptr && field) { /* dot-connected field on an argument is not supported. */ trace_probe_log_err(ctx->offset + field - varname, NOSUP_DAT_ARG); return -EOPNOTSUPP; }
if (ctx->flags & TPARG_FL_TEVENT) { ret = parse_trace_event(varname, code, ctx); if (ret < 0) { trace_probe_log_err(ctx->offset, BAD_ATTACH_ARG); return ret; } /* TEVENT is only here via a typecast */ if (WARN_ON_ONCE(ctx->struct_btf == NULL)) return -EINVAL; type = ctx->last_struct; goto found_type; }
if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) { code->op = FETCH_OP_RETVAL; /* Check whether the function return type is not void */ if (query_btf_context(ctx) == 0) { if (ctx->proto->type == 0) { trace_probe_log_err(ctx->offset, NO_RETVAL); return -ENOENT; } tid = ctx->proto->type; goto found; } if (field) { trace_probe_log_err(ctx->offset + field - varname, NO_BTF_ENTRY); return -ENOENT; } return 0; }
if (!ctx->btf) { ret = query_btf_context(ctx); if (ret < 0 || ctx->nr_params == 0) { trace_probe_log_err(ctx->offset, NO_BTF_ENTRY); return -ENOENT; } } params = ctx->params;
for (i = 0; i < ctx->nr_params; i++) { const char *name = btf_name_by_offset(ctx->btf, params[i].name_off);
if (name && !strcmp(name, varname)) { if (tparg_is_function_entry(ctx->flags)) { code->op = FETCH_OP_ARG; if (ctx->flags & TPARG_FL_TPOINT) code->param = i + 1; else code->param = i; } else if (tparg_is_function_return(ctx->flags)) { code->op = FETCH_OP_EDATA; ret = __store_entry_arg(ctx->tp, i); if (ret < 0) { /* internal error */ return ret; } code->offset = ret; } tid = params[i].type; goto found; } } trace_probe_log_err(ctx->offset, NO_BTFARG); return -ENOENT;
found: type = btf_type_skip_modifiers(ctx->btf, tid, &tid);found_type: if (!type) { trace_probe_log_err(ctx->offset, BAD_BTF_TID); return -EINVAL; } /* Initialize the last type information */ ctx->last_type = type; ctx->last_bitoffs = 0; ctx->last_bitsize = 0; if (field) { ctx->offset += field - varname; return parse_btf_field(field, type, pcode, end, ctx); } return 0;}
static const struct fetch_type *find_fetch_type_from_btf_type( struct traceprobe_parse_context *ctx){ struct btf *btf = ctx_btf(ctx); const char *typestr = NULL;
if (btf && ctx->last_type) typestr = fetch_type_from_btf_type(btf, ctx->last_type, ctx);
return find_fetch_type(typestr, ctx->flags);}
static int parse_btf_bitfield(struct fetch_insn **pcode, struct traceprobe_parse_context *ctx){ struct fetch_insn *code = *pcode;
if ((ctx->last_bitsize % 8 == 0) && ctx->last_bitoffs == 0) return 0;
code++; if (code->op != FETCH_OP_NOP) { trace_probe_log_err(ctx->offset, TOO_MANY_OPS); return -EINVAL; } *pcode = code;
code->op = FETCH_OP_MOD_BF; code->lshift = 64 - (ctx->last_bitsize + ctx->last_bitoffs); code->rshift = 64 - ctx->last_bitsize; code->basesize = 64 / 8; return 0;}
static int query_btf_struct(const char *sname, struct traceprobe_parse_context *ctx){ struct btf *btf = NULL; int id;
/* A struct_btf should only be used by a single argument */ if (WARN_ON_ONCE(ctx->struct_btf)) { btf_put(ctx->struct_btf); ctx->struct_btf = NULL; }
id = bpf_find_btf_id(sname, BTF_KIND_STRUCT, &btf); if (id < 0) return id; ctx->struct_btf = btf; ctx->last_struct = btf_type_by_id(ctx->struct_btf, id); return 0;}
static int handle_typecast(char *arg, struct fetch_insn **pcode, struct fetch_insn *end, struct traceprobe_parse_context *ctx){ char *tmp; int ret;
/* Currently this only works for eprobes */ if (!(ctx->flags & TPARG_FL_TEVENT)) { trace_probe_log_err(ctx->offset, TYPECAST_NOT_EVENT); return -EINVAL; }
tmp = strchr(arg, ')'); if (!tmp) { trace_probe_log_err(ctx->offset + strlen(arg), DEREF_OPEN_BRACE); return -EINVAL; } *tmp = '\0'; ret = query_btf_struct(arg + 1, ctx); *tmp = ')';
if (ret < 0) { trace_probe_log_err(ctx->offset + 1, NO_PTR_STRCT); return -EINVAL; }
tmp++;
ctx->offset += tmp - arg; ret = parse_btf_arg(tmp, pcode, end, ctx); return ret;}
#else /* !CONFIG_PROBE_EVENTS_BTF_ARGS */
static void clear_struct_btf(struct traceprobe_parse_context *ctx){ ctx->struct_btf = NULL;}
static void clear_btf_context(struct traceprobe_parse_context *ctx){ ctx->btf = NULL;}
static int query_btf_context(struct traceprobe_parse_context *ctx){ return -EOPNOTSUPP;}
static int parse_btf_arg(char *varname, struct fetch_insn **pcode, struct fetch_insn *end, struct traceprobe_parse_context *ctx){ trace_probe_log_err(ctx->offset, NOSUP_BTFARG); return -EOPNOTSUPP;}
static int parse_btf_bitfield(struct fetch_insn **pcode, struct traceprobe_parse_context *ctx){ trace_probe_log_err(ctx->offset, NOSUP_BTFARG); return -EOPNOTSUPP;}
#define find_fetch_type_from_btf_type(ctx) \ find_fetch_type(NULL, ctx->flags)
static int check_prepare_btf_string_fetch(char *typename, struct fetch_insn **pcode, struct traceprobe_parse_context *ctx){ return 0;}
static int handle_typecast(char *arg, struct fetch_insn **pcode, struct fetch_insn *end, struct traceprobe_parse_context *ctx){ trace_probe_log_err(ctx->offset, NOSUP_BTFARG); return -EOPNOTSUPP;}
#endif /* CONFIG_PROBE_EVENTS_BTF_ARGS */
#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
static void store_entry_arg_at(struct fetch_insn *code, int argnum, int offset){ code[0].op = FETCH_OP_ARG; code[0].param = argnum; code[1].op = FETCH_OP_ST_EDATA; code[1].offset = offset;}
static int get_entry_arg_max_offset(struct probe_entry_arg *earg){ int i, max_offset = 0;
/* * earg->code[] array has an operation sequence which is run in * the entry handler. * The sequence stopped by FETCH_OP_END and each data stored in * the entry data buffer by FETCH_OP_ST_EDATA. The FETCH_OP_ST_EDATA * stores the data at the data buffer + its offset, and all data are * "unsigned long" size. The offset must be increased when a data is * stored. Thus we need to find the last FETCH_OP_ST_EDATA in the * code array. */ for (i = 0; i < earg->size - 1 && earg->code[i].op != FETCH_OP_END; i++) { if (earg->code[i].op == FETCH_OP_ST_EDATA) if (earg->code[i].offset > max_offset) max_offset = earg->code[i].offset; } return max_offset;}
/* * Add the entry code to store the 'argnum'th parameter and return the offset * in the entry data buffer where the data will be stored. */static int __store_entry_arg(struct trace_probe *tp, int argnum){ struct probe_entry_arg *earg = tp->entry_arg; int i, offset, last_offset = 0;
if (!earg) { earg = kzalloc_flex(*earg, code, 2 * tp->nr_args + 1); if (!earg) return -ENOMEM; earg->size = 2 * tp->nr_args + 1; /* Fill the code buffer with 'end' to simplify it */ for (i = 0; i < earg->size; i++) earg->code[i].op = FETCH_OP_END; tp->entry_arg = earg; store_entry_arg_at(earg->code, argnum, 0); return 0; }
/* * NOTE: if anyone change the following rule, please rewrite this. * The entry code array is filled with the pair of * * [FETCH_OP_ARG(argnum)] * [FETCH_OP_ST_EDATA(offset of entry data buffer)] * * and the rest of entries are filled with [FETCH_OP_END]. * The offset should be incremented, thus the last pair should * have the largest offset. */
/* Search the offset for the sprcified argnum. */ for (i = 0; i < earg->size - 1 && earg->code[i].op != FETCH_OP_END; i += 2) { if (WARN_ON_ONCE(earg->code[i].op != FETCH_OP_ARG)) return -EINVAL;
if (earg->code[i].param != argnum) continue;
if (WARN_ON_ONCE(earg->code[i + 1].op != FETCH_OP_ST_EDATA)) return -EINVAL;
return earg->code[i + 1].offset; } /* Not found, append new entry if possible. */ if (i >= earg->size - 1) return -ENOSPC;
/* The last entry must have the largest offset. */ if (i != 0) { if (WARN_ON_ONCE(earg->code[i - 1].op != FETCH_OP_ST_EDATA)) return -EINVAL; last_offset = earg->code[i - 1].offset; }
offset = last_offset + sizeof(unsigned long); store_entry_arg_at(&earg->code[i], argnum, offset); return offset;}
int traceprobe_get_entry_data_size(struct trace_probe *tp){ struct probe_entry_arg *earg = tp->entry_arg;
if (!earg) return 0;
return get_entry_arg_max_offset(earg) + sizeof(unsigned long);}
void store_trace_entry_data(void *edata, struct trace_probe *tp, struct pt_regs *regs){ struct probe_entry_arg *earg = tp->entry_arg; unsigned long val = 0; int i;
if (!earg) return;
for (i = 0; i < earg->size; i++) { struct fetch_insn *code = &earg->code[i];
switch (code->op) { case FETCH_OP_ARG: val = regs_get_kernel_argument(regs, code->param); break; case FETCH_OP_ST_EDATA: *(unsigned long *)((unsigned long)edata + code->offset) = val; break; case FETCH_OP_END: goto end; default: break; } }end: return;}NOKPROBE_SYMBOL(store_trace_entry_data)#endif
#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
/* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */static int parse_probe_vars(char *orig_arg, const struct fetch_type *t, struct fetch_insn **pcode, struct fetch_insn *end, struct traceprobe_parse_context *ctx){ struct fetch_insn *code = *pcode; int err = TP_ERR_BAD_VAR; char *arg = orig_arg + 1; unsigned long param; int ret = 0; int len;
if (ctx->flags & TPARG_FL_TEVENT) { if (parse_trace_event(arg, code, ctx) < 0) { /* 'comm' should be checked after field parsing. */ if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) { code->op = FETCH_OP_COMM; return 0; } goto inval; } return 0; }
if (str_has_prefix(arg, "retval")) { if (!(ctx->flags & TPARG_FL_RETURN)) { err = TP_ERR_RETVAL_ON_PROBE; goto inval; } if (!(ctx->flags & TPARG_FL_KERNEL) || !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) { code->op = FETCH_OP_RETVAL; return 0; } return parse_btf_arg(orig_arg, pcode, end, ctx); }
len = str_has_prefix(arg, "stack"); if (len) {
if (arg[len] == '\0') { code->op = FETCH_OP_STACKP; return 0; }
if (isdigit(arg[len])) { ret = kstrtoul(arg + len, 10, ¶m); if (ret) goto inval;
if ((ctx->flags & TPARG_FL_KERNEL) && param > PARAM_MAX_STACK) { err = TP_ERR_BAD_STACK_NUM; goto inval; } code->op = FETCH_OP_STACK; code->param = (unsigned int)param; return 0; } goto inval; }
if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) { code->op = FETCH_OP_COMM; return 0; }
#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API len = str_has_prefix(arg, "arg"); if (len) { ret = kstrtoul(arg + len, 10, ¶m); if (ret) goto inval;
if (!param || param > PARAM_MAX_STACK) { err = TP_ERR_BAD_ARG_NUM; goto inval; } param--; /* argN starts from 1, but internal arg[N] starts from 0 */
if (tparg_is_function_entry(ctx->flags)) { code->op = FETCH_OP_ARG; code->param = (unsigned int)param; /* * The tracepoint probe will probe a stub function, and the * first parameter of the stub is a dummy and should be ignored. */ if (ctx->flags & TPARG_FL_TPOINT) code->param++; } else if (tparg_is_function_return(ctx->flags)) { /* function entry argument access from return probe */ ret = __store_entry_arg(ctx->tp, param); if (ret < 0) /* This error should be an internal error */ return ret;
code->op = FETCH_OP_EDATA; code->offset = ret; } else { err = TP_ERR_NOFENTRY_ARGS; goto inval; } return 0; }#endif
inval: __trace_probe_log_err(ctx->offset, err); return -EINVAL;}
static int str_to_immediate(char *str, unsigned long *imm){ if (isdigit(str[0])) return kstrtoul(str, 0, imm); else if (str[0] == '-') return kstrtol(str, 0, (long *)imm); else if (str[0] == '+') return kstrtol(str + 1, 0, (long *)imm); return -EINVAL;}
static int __parse_imm_string(char *str, char **pbuf, int offs){ size_t len = strlen(str);
if (!len || str[len - 1] != '"') { trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE); return -EINVAL; } *pbuf = kstrndup(str, len - 1, GFP_KERNEL); if (!*pbuf) return -ENOMEM; return 0;}
/* Recursive argument parser */static intparse_probe_arg(char *arg, const struct fetch_type *type, struct fetch_insn **pcode, struct fetch_insn *end, struct traceprobe_parse_context *ctx){ struct fetch_insn *code = *pcode; unsigned long param; int deref = FETCH_OP_DEREF; long offset = 0; char *tmp; int ret = 0;
switch (arg[0]) { case '$': ret = parse_probe_vars(arg, type, pcode, end, ctx); break;
case '%': /* named register */ if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) { /* eprobe and fprobe do not handle registers */ trace_probe_log_err(ctx->offset, BAD_VAR); break; } ret = regs_query_register_offset(arg + 1); if (ret >= 0) { code->op = FETCH_OP_REG; code->param = (unsigned int)ret; ret = 0; } else trace_probe_log_err(ctx->offset, BAD_REG_NAME); break;
case '@': /* memory, file-offset or symbol */ if (isdigit(arg[1])) { ret = kstrtoul(arg + 1, 0, ¶m); if (ret) { trace_probe_log_err(ctx->offset, BAD_MEM_ADDR); break; } /* load address */ code->op = FETCH_OP_IMM; code->immediate = param; } else if (arg[1] == '+') { /* kprobes don't support file offsets */ if (ctx->flags & TPARG_FL_KERNEL) { trace_probe_log_err(ctx->offset, FILE_ON_KPROBE); return -EINVAL; } ret = kstrtol(arg + 2, 0, &offset); if (ret) { trace_probe_log_err(ctx->offset, BAD_FILE_OFFS); break; }
code->op = FETCH_OP_FOFFS; code->immediate = (unsigned long)offset; // imm64? offset = 0; } else { /* uprobes don't support symbols */ if (!(ctx->flags & TPARG_FL_KERNEL)) { trace_probe_log_err(ctx->offset, SYM_ON_UPROBE); return -EINVAL; } /* Preserve symbol for updating */ code->op = FETCH_NOP_SYMBOL; code->data = kstrdup(arg + 1, GFP_KERNEL); if (!code->data) return -ENOMEM; if (++code == end) { trace_probe_log_err(ctx->offset, TOO_MANY_OPS); return -EINVAL; } code->op = FETCH_OP_IMM; code->immediate = 0; } /* These are fetching from memory */ if (++code == end) { trace_probe_log_err(ctx->offset, TOO_MANY_OPS); return -EINVAL; } *pcode = code; code->op = FETCH_OP_DEREF; code->offset = offset; break;
case '+': /* deref memory */ case '-': if (arg[1] == 'u') { deref = FETCH_OP_UDEREF; arg[1] = arg[0]; arg++; } if (arg[0] == '+') arg++; /* Skip '+', because kstrtol() rejects it. */ tmp = strchr(arg, '('); if (!tmp) { trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE); return -EINVAL; } *tmp = '\0'; ret = kstrtol(arg, 0, &offset); if (ret) { trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS); break; } ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0); arg = tmp + 1; tmp = strrchr(arg, ')'); if (!tmp) { trace_probe_log_err(ctx->offset + strlen(arg), DEREF_OPEN_BRACE); return -EINVAL; } else { const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags); int cur_offs = ctx->offset;
*tmp = '\0'; ret = parse_probe_arg(arg, t2, &code, end, ctx); if (ret) break; ctx->offset = cur_offs; if (code->op == FETCH_OP_COMM || code->op == FETCH_OP_DATA) { trace_probe_log_err(ctx->offset, COMM_CANT_DEREF); return -EINVAL; } if (++code == end) { trace_probe_log_err(ctx->offset, TOO_MANY_OPS); return -EINVAL; } *pcode = code;
code->op = deref; code->offset = offset; /* Reset the last type if used */ ctx->last_type = NULL; } break; case '\\': /* Immediate value */ if (arg[1] == '"') { /* Immediate string */ ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2); if (ret) break; code->op = FETCH_OP_DATA; code->data = tmp; } else { ret = str_to_immediate(arg + 1, &code->immediate); if (ret) trace_probe_log_err(ctx->offset + 1, BAD_IMM); else code->op = FETCH_OP_IMM; } break; case '(': ret = handle_typecast(arg, pcode, end, ctx); break; default: if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */ if (!tparg_is_function_entry(ctx->flags) && !tparg_is_function_return(ctx->flags)) { trace_probe_log_err(ctx->offset, NOSUP_BTFARG); return -EINVAL; } ret = parse_btf_arg(arg, pcode, end, ctx); break; } } if (!ret && code->op == FETCH_OP_NOP) { /* Parsed, but do not find fetch method */ trace_probe_log_err(ctx->offset, BAD_FETCH_ARG); ret = -EINVAL; } return ret;}
/* Bitfield type needs to be parsed into a fetch function */static int __parse_bitfield_probe_arg(const char *bf, const struct fetch_type *t, struct fetch_insn **pcode){ struct fetch_insn *code = *pcode; unsigned long bw, bo; char *tail;
if (*bf != 'b') return 0;
bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
if (bw == 0 || *tail != '@') return -EINVAL;
bf = tail + 1; bo = simple_strtoul(bf, &tail, 0);
if (tail == bf || *tail != '/') return -EINVAL; code++; if (code->op != FETCH_OP_NOP) return -EINVAL; *pcode = code;
code->op = FETCH_OP_MOD_BF; code->lshift = BYTES_TO_BITS(t->size) - (bw + bo); code->rshift = BYTES_TO_BITS(t->size) - bw; code->basesize = t->size;
return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;}
/* Split type part from @arg and return it. */static char *parse_probe_arg_type(char *arg, struct probe_arg *parg, struct traceprobe_parse_context *ctx){ char *t = NULL, *t2, *t3; int offs;
t = strchr(arg, ':'); if (t) { *t++ = '\0'; t2 = strchr(t, '['); if (t2) { *t2++ = '\0'; t3 = strchr(t2, ']'); if (!t3) { offs = t2 + strlen(t2) - arg;
trace_probe_log_err(ctx->offset + offs, ARRAY_NO_CLOSE); return ERR_PTR(-EINVAL); } else if (t3[1] != '\0') { trace_probe_log_err(ctx->offset + t3 + 1 - arg, BAD_ARRAY_SUFFIX); return ERR_PTR(-EINVAL); } *t3 = '\0'; if (kstrtouint(t2, 0, &parg->count) || !parg->count) { trace_probe_log_err(ctx->offset + t2 - arg, BAD_ARRAY_NUM); return ERR_PTR(-EINVAL); } if (parg->count > MAX_ARRAY_LEN) { trace_probe_log_err(ctx->offset + t2 - arg, ARRAY_TOO_BIG); return ERR_PTR(-EINVAL); } } } offs = t ? t - arg : 0;
/* * Since $comm and immediate string can not be dereferenced, * we can find those by strcmp. But ignore for eprobes. */ if (!(ctx->flags & TPARG_FL_TEVENT) && (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 || strncmp(arg, "\\\"", 2) == 0)) { /* The type of $comm must be "string", and not an array type. */ if (parg->count || (t && strcmp(t, "string"))) { trace_probe_log_err(ctx->offset + offs, NEED_STRING_TYPE); return ERR_PTR(-EINVAL); } parg->type = find_fetch_type("string", ctx->flags); } else parg->type = find_fetch_type(t, ctx->flags);
if (!parg->type) { trace_probe_log_err(ctx->offset + offs, BAD_TYPE); return ERR_PTR(-EINVAL); }
return t;}
/* After parsing, adjust the fetch_insn according to the probe_arg */static int finalize_fetch_insn(struct fetch_insn *code, struct probe_arg *parg, char *type, int type_offset, struct traceprobe_parse_context *ctx){ struct fetch_insn *scode; int ret;
/* Store operation */ if (parg->type->is_string) { /* Check bad combination of the type and the last fetch_insn. */ if (!strcmp(parg->type->name, "symstr")) { if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK && code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG && code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) { trace_probe_log_err(ctx->offset + type_offset, BAD_SYMSTRING); return -EINVAL; } } else { if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF && code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM && code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) { trace_probe_log_err(ctx->offset + type_offset, BAD_STRING); return -EINVAL; } }
if (!strcmp(parg->type->name, "symstr") || (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM || code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG || parg->count) { /* * IMM, DATA and COMM is pointing actual address, those * must be kept, and if parg->count != 0, this is an * array of string pointers instead of string address * itself. * For the symstr, it doesn't need to dereference, thus * it just get the value. */ code++; if (code->op != FETCH_OP_NOP) { trace_probe_log_err(ctx->offset, TOO_MANY_OPS); return -EINVAL; } }
/* If op == DEREF, replace it with STRING */ if (!strcmp(parg->type->name, "ustring") || code->op == FETCH_OP_UDEREF) code->op = FETCH_OP_ST_USTRING; else if (!strcmp(parg->type->name, "symstr")) code->op = FETCH_OP_ST_SYMSTR; else code->op = FETCH_OP_ST_STRING; code->size = parg->type->size; parg->dynamic = true; } else if (code->op == FETCH_OP_DEREF) { code->op = FETCH_OP_ST_MEM; code->size = parg->type->size; } else if (code->op == FETCH_OP_UDEREF) { code->op = FETCH_OP_ST_UMEM; code->size = parg->type->size; } else { code++; if (code->op != FETCH_OP_NOP) { trace_probe_log_err(ctx->offset, TOO_MANY_OPS); return -E2BIG; } code->op = FETCH_OP_ST_RAW; code->size = parg->type->size; }
/* Save storing fetch_insn. */ scode = code;
/* Modify operation */ if (type != NULL) { /* Bitfield needs a special fetch_insn. */ ret = __parse_bitfield_probe_arg(type, parg->type, &code); if (ret) { trace_probe_log_err(ctx->offset + type_offset, BAD_BITFIELD); return ret; } } else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) && ctx->last_type) { /* If user not specified the type, try parsing BTF bitfield. */ ret = parse_btf_bitfield(&code, ctx); if (ret) return ret; }
/* Loop(Array) operation */ if (parg->count) { if (scode->op != FETCH_OP_ST_MEM && scode->op != FETCH_OP_ST_STRING && scode->op != FETCH_OP_ST_USTRING) { trace_probe_log_err(ctx->offset + type_offset, BAD_STRING); return -EINVAL; } code++; if (code->op != FETCH_OP_NOP) { trace_probe_log_err(ctx->offset, TOO_MANY_OPS); return -E2BIG; } code->op = FETCH_OP_LP_ARRAY; code->param = parg->count; }
/* Finalize the fetch_insn array. */ code++; code->op = FETCH_OP_END;
return 0;}
/* String length checking wrapper */static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, struct probe_arg *parg, struct traceprobe_parse_context *ctx){ struct fetch_insn *code, *tmp = NULL; char *type, *arg __free(kfree) = NULL; int ret, len;
len = strlen(argv); if (len > MAX_ARGSTR_LEN) { trace_probe_log_err(ctx->offset, ARG_TOO_LONG); return -E2BIG; } else if (len == 0) { trace_probe_log_err(ctx->offset, NO_ARG_BODY); return -EINVAL; }
arg = kstrdup(argv, GFP_KERNEL); if (!arg) return -ENOMEM;
parg->comm = kstrdup(arg, GFP_KERNEL); if (!parg->comm) return -ENOMEM;
type = parse_probe_arg_type(arg, parg, ctx); if (IS_ERR(type)) return PTR_ERR(type);
code = tmp = kzalloc_objs(*code, FETCH_INSN_MAX); if (!code) return -ENOMEM; code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
ctx->last_type = NULL; ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1], ctx); if (ret < 0) goto fail;
/* Update storing type if BTF is available */ if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) && ctx->last_type) { if (!type) { parg->type = find_fetch_type_from_btf_type(ctx); } else if (strstr(type, "string")) { ret = check_prepare_btf_string_fetch(type, &code, ctx); if (ret) goto fail; } } parg->offset = *size; *size += parg->type->size * (parg->count ?: 1);
if (*size > MAX_PROBE_EVENT_SIZE) { ret = -E2BIG; trace_probe_log_err(ctx->offset, EVENT_TOO_BIG); goto fail; }
if (parg->count) { len = strlen(parg->type->fmttype) + 6; parg->fmt = kmalloc(len, GFP_KERNEL); if (!parg->fmt) { ret = -ENOMEM; goto fail; } snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype, parg->count); }
ret = finalize_fetch_insn(code, parg, type, type ? type - arg : 0, ctx); if (ret < 0) goto fail;
for (; code < tmp + FETCH_INSN_MAX; code++) if (code->op == FETCH_OP_END) break; /* Shrink down the code buffer */ parg->code = kzalloc_objs(*code, code - tmp + 1); if (!parg->code) ret = -ENOMEM; else memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
fail: if (ret < 0) { for (code = tmp; code < tmp + FETCH_INSN_MAX; code++) if (code->op == FETCH_NOP_SYMBOL || code->op == FETCH_OP_DATA) kfree(code->data); } kfree(tmp);
/* struct_btf should not be passed to other arguments */ clear_struct_btf(ctx);
return ret;}
/* Return 1 if name is reserved or already used by another argument */static int traceprobe_conflict_field_name(const char *name, struct probe_arg *args, int narg){ int i;
for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++) if (strcmp(reserved_field_names[i], name) == 0) return 1;
for (i = 0; i < narg; i++) if (strcmp(args[i].name, name) == 0) return 1;
return 0;}
static char *generate_probe_arg_name(const char *arg, int idx){ char *name = NULL; const char *end;
/* * If argument name is omitted, try arg as a name (BTF variable) * or "argN". */ if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) { end = strchr(arg, ':'); if (!end) end = arg + strlen(arg);
name = kmemdup_nul(arg, end - arg, GFP_KERNEL); if (!name || !is_good_name(name)) { kfree(name); name = NULL; } }
if (!name) name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
return name;}
int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg, struct traceprobe_parse_context *ctx){ struct probe_arg *parg = &tp->args[i]; const char *body;
ctx->tp = tp; body = strchr(arg, '='); if (body) { if (body - arg > MAX_ARG_NAME_LEN) { trace_probe_log_err(0, ARG_NAME_TOO_LONG); return -EINVAL; } else if (body == arg) { trace_probe_log_err(0, NO_ARG_NAME); return -EINVAL; } parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL); body++; } else { parg->name = generate_probe_arg_name(arg, i); body = arg; } if (!parg->name) return -ENOMEM;
if (!is_good_name(parg->name)) { trace_probe_log_err(0, BAD_ARG_NAME); return -EINVAL; } if (traceprobe_conflict_field_name(parg->name, tp->args, i)) { trace_probe_log_err(0, USED_ARG_NAME); return -EINVAL; } ctx->offset = body - arg; /* Parse fetch argument */ return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);}
void traceprobe_free_probe_arg(struct probe_arg *arg){ struct fetch_insn *code = arg->code;
while (code && code->op != FETCH_OP_END) { if (code->op == FETCH_NOP_SYMBOL || code->op == FETCH_OP_DATA) kfree(code->data); code++; } kfree(arg->code); kfree(arg->name); kfree(arg->comm); kfree(arg->fmt);}
static int argv_has_var_arg(int argc, const char *argv[], int *args_idx, struct traceprobe_parse_context *ctx){ int i, found = 0;
for (i = 0; i < argc; i++) if (str_has_prefix(argv[i], "$arg")) { trace_probe_log_set_index(i + 2);
if (!tparg_is_function_entry(ctx->flags) && !tparg_is_function_return(ctx->flags)) { trace_probe_log_err(0, NOFENTRY_ARGS); return -EINVAL; }
if (isdigit(argv[i][4])) { found = 1; continue; }
if (argv[i][4] != '*') { trace_probe_log_err(0, BAD_VAR); return -EINVAL; }
if (*args_idx >= 0 && *args_idx < argc) { trace_probe_log_err(0, DOUBLE_ARGS); return -EINVAL; } found = 1; *args_idx = i; }
return found;}
static int sprint_nth_btf_arg(int idx, const char *type, char *buf, int bufsize, struct traceprobe_parse_context *ctx){ const char *name; int ret;
if (idx >= ctx->nr_params) { trace_probe_log_err(0, NO_BTFARG); return -ENOENT; } name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off); if (!name) { trace_probe_log_err(0, NO_BTF_ENTRY); return -ENOENT; } ret = snprintf(buf, bufsize, "%s%s", name, type); if (ret >= bufsize) { trace_probe_log_err(0, ARGS_2LONG); return -E2BIG; } return ret;}
/* Return new_argv which must be freed after use */const char **traceprobe_expand_meta_args(int argc, const char *argv[], int *new_argc, char *buf, int bufsize, struct traceprobe_parse_context *ctx){ const struct btf_param *params = NULL; int i, j, n, used, ret, args_idx = -1; const char **new_argv __free(kfree) = NULL;
ret = argv_has_var_arg(argc, argv, &args_idx, ctx); if (ret < 0) return ERR_PTR(ret);
if (!ret) { *new_argc = argc; return NULL; }
ret = query_btf_context(ctx); if (ret < 0 || ctx->nr_params == 0) { if (args_idx != -1) { /* $arg* requires BTF info */ trace_probe_log_err(0, NOSUP_BTFARG); return (const char **)params; } *new_argc = argc; return NULL; }
if (args_idx >= 0) *new_argc = argc + ctx->nr_params - 1; else *new_argc = argc;
new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL); if (!new_argv) return ERR_PTR(-ENOMEM);
used = 0; for (i = 0, j = 0; i < argc; i++) { trace_probe_log_set_index(i + 2); if (i == args_idx) { for (n = 0; n < ctx->nr_params; n++) { ret = sprint_nth_btf_arg(n, "", buf + used, bufsize - used, ctx); if (ret < 0) return ERR_PTR(ret);
new_argv[j++] = buf + used; used += ret + 1; } continue; }
if (str_has_prefix(argv[i], "$arg")) { char *type = NULL;
n = simple_strtoul(argv[i] + 4, &type, 10); if (type && !(*type == ':' || *type == '\0')) { trace_probe_log_err(0, BAD_VAR); return ERR_PTR(-ENOENT); } /* Note: $argN starts from $arg1 */ ret = sprint_nth_btf_arg(n - 1, type, buf + used, bufsize - used, ctx); if (ret < 0) return ERR_PTR(ret); new_argv[j++] = buf + used; used += ret + 1; } else new_argv[j++] = argv[i]; }
return_ptr(new_argv);}
/* @buf: *buf must be equal to NULL. Caller must to free *buf */int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf){ int i, used, ret; const int bufsize = MAX_DENTRY_ARGS_LEN; char *tmpbuf __free(kfree) = NULL;
if (*buf) return -EINVAL;
used = 0; for (i = 0; i < argc; i++) { char *tmp __free(kfree) = NULL; char *equal; size_t arg_len;
if (!glob_match("*:%p[dD]", argv[i])) continue;
if (!tmpbuf) { tmpbuf = kmalloc(bufsize, GFP_KERNEL); if (!tmpbuf) return -ENOMEM; }
tmp = kstrdup(argv[i], GFP_KERNEL); if (!tmp) return -ENOMEM;
equal = strchr(tmp, '='); if (equal) *equal = '\0'; arg_len = strlen(argv[i]); tmp[arg_len - 4] = '\0'; if (argv[i][arg_len - 1] == 'd') ret = snprintf(tmpbuf + used, bufsize - used, "%s%s+0x0(+0x%zx(%s)):string", equal ? tmp : "", equal ? "=" : "", offsetof(struct dentry, d_name.name), equal ? equal + 1 : tmp); else ret = snprintf(tmpbuf + used, bufsize - used, "%s%s+0x0(+0x%zx(+0x%zx(%s))):string", equal ? tmp : "", equal ? "=" : "", offsetof(struct dentry, d_name.name), offsetof(struct file, f_path.dentry), equal ? equal + 1 : tmp);
if (ret >= bufsize - used) return -ENOMEM; argv[i] = tmpbuf + used; used += ret + 1; }
*buf = no_free_ptr(tmpbuf); return 0;}
void traceprobe_finish_parse(struct traceprobe_parse_context *ctx){ clear_btf_context(ctx);}
int traceprobe_update_arg(struct probe_arg *arg){ struct fetch_insn *code = arg->code; long offset; char *tmp; char c; int ret = 0;
while (code && code->op != FETCH_OP_END) { if (code->op == FETCH_NOP_SYMBOL) { if (code[1].op != FETCH_OP_IMM) return -EINVAL;
tmp = strpbrk(code->data, "+-"); if (tmp) c = *tmp; ret = traceprobe_split_symbol_offset(code->data, &offset); if (ret) return ret;
code[1].immediate = (unsigned long)kallsyms_lookup_name(code->data); if (tmp) *tmp = c; if (!code[1].immediate) return -ENOENT; code[1].immediate += offset; } code++; } return 0;}
/* When len=0, we just calculate the needed length */#define LEN_OR_ZERO (len > pos ? len - pos : 0)static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, enum probe_print_type ptype){ struct probe_arg *parg; int i, j; int pos = 0; const char *fmt, *arg;
switch (ptype) { case PROBE_PRINT_NORMAL: fmt = "(%lx)"; arg = ", REC->" FIELD_STRING_IP; break; case PROBE_PRINT_RETURN: fmt = "(%lx <- %lx)"; arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP; break; case PROBE_PRINT_EVENT: fmt = ""; arg = ""; break; default: WARN_ON_ONCE(1); return 0; }
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
for (i = 0; i < tp->nr_args; i++) { parg = tp->args + i; pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name); if (parg->count) { pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s", parg->type->fmt); for (j = 1; j < parg->count; j++) pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s", parg->type->fmt); pos += snprintf(buf + pos, LEN_OR_ZERO, "}"); } else pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", parg->type->fmt); }
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
for (i = 0; i < tp->nr_args; i++) { parg = tp->args + i; if (parg->count) { if (parg->type->is_string) fmt = ", __get_str(%s[%d])"; else fmt = ", REC->%s[%d]"; for (j = 0; j < parg->count; j++) pos += snprintf(buf + pos, LEN_OR_ZERO, fmt, parg->name, j); } else { if (parg->type->is_string) fmt = ", __get_str(%s)"; else fmt = ", REC->%s"; pos += snprintf(buf + pos, LEN_OR_ZERO, fmt, parg->name); } }
/* return the length of print_fmt */ return pos;}#undef LEN_OR_ZERO
int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype){ struct trace_event_call *call = trace_probe_event_call(tp); int len; char *print_fmt;
/* First: called with 0 length to calculate the needed length */ len = __set_print_fmt(tp, NULL, 0, ptype); print_fmt = kmalloc(len + 1, GFP_KERNEL); if (!print_fmt) return -ENOMEM;
/* Second: actually write the @print_fmt */ __set_print_fmt(tp, print_fmt, len + 1, ptype); call->print_fmt = print_fmt;
return 0;}
int traceprobe_define_arg_fields(struct trace_event_call *event_call, size_t offset, struct trace_probe *tp){ int ret, i;
/* Set argument names as fields */ for (i = 0; i < tp->nr_args; i++) { struct probe_arg *parg = &tp->args[i]; const char *fmt = parg->type->fmttype; int size = parg->type->size;
if (parg->fmt) fmt = parg->fmt; if (parg->count) size *= parg->count; ret = trace_define_field(event_call, fmt, parg->name, offset + parg->offset, size, parg->type->is_signed, FILTER_OTHER); if (ret) return ret; } return 0;}
static void trace_probe_event_free(struct trace_probe_event *tpe){ kfree(tpe->class.system); kfree(tpe->call.name); kfree(tpe->call.print_fmt); kfree(tpe);}
int trace_probe_append(struct trace_probe *tp, struct trace_probe *to){ if (trace_probe_has_sibling(tp)) return -EBUSY;
list_del_init(&tp->list); trace_probe_event_free(tp->event);
tp->event = to->event; list_add_tail(&tp->list, trace_probe_probe_list(to));
return 0;}
void trace_probe_unlink(struct trace_probe *tp){ list_del_init(&tp->list); if (list_empty(trace_probe_probe_list(tp))) trace_probe_event_free(tp->event); tp->event = NULL;}
void trace_probe_cleanup(struct trace_probe *tp){ int i;
for (i = 0; i < tp->nr_args; i++) traceprobe_free_probe_arg(&tp->args[i]);
if (tp->entry_arg) { kfree(tp->entry_arg); tp->entry_arg = NULL; }
if (tp->event) trace_probe_unlink(tp);}
int trace_probe_init(struct trace_probe *tp, const char *event, const char *group, bool alloc_filter, int nargs){ struct trace_event_call *call; size_t size = sizeof(struct trace_probe_event); int ret = 0;
if (!event || !group) return -EINVAL;
if (alloc_filter) size += sizeof(struct trace_uprobe_filter);
tp->event = kzalloc(size, GFP_KERNEL); if (!tp->event) return -ENOMEM;
INIT_LIST_HEAD(&tp->event->files); INIT_LIST_HEAD(&tp->event->class.fields); INIT_LIST_HEAD(&tp->event->probes); INIT_LIST_HEAD(&tp->list); list_add(&tp->list, &tp->event->probes);
call = trace_probe_event_call(tp); call->class = &tp->event->class; call->name = kstrdup(event, GFP_KERNEL); if (!call->name) { ret = -ENOMEM; goto error; }
tp->event->class.system = kstrdup(group, GFP_KERNEL); if (!tp->event->class.system) { ret = -ENOMEM; goto error; }
tp->nr_args = nargs; /* Make sure pointers in args[] are NULL */ if (nargs) memset(tp->args, 0, sizeof(tp->args[0]) * nargs);
return 0;
error: trace_probe_cleanup(tp); return ret;}
static struct trace_event_call *find_trace_event_call(const char *system, const char *event_name){ struct trace_event_call *tp_event; const char *name;
list_for_each_entry(tp_event, &ftrace_events, list) { if (!tp_event->class->system || strcmp(system, tp_event->class->system)) continue; name = trace_event_name(tp_event); if (!name || strcmp(event_name, name)) continue; return tp_event; }
return NULL;}
int trace_probe_register_event_call(struct trace_probe *tp){ struct trace_event_call *call = trace_probe_event_call(tp); int ret;
lockdep_assert_held(&event_mutex);
if (find_trace_event_call(trace_probe_group_name(tp), trace_probe_name(tp))) return -EEXIST;
ret = register_trace_event(&call->event); if (!ret) return -ENODEV;
ret = trace_add_event_call(call); if (ret) unregister_trace_event(&call->event);
return ret;}
int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file){ struct event_file_link *link;
link = kmalloc_obj(*link); if (!link) return -ENOMEM;
link->file = file; INIT_LIST_HEAD(&link->list); list_add_tail_rcu(&link->list, &tp->event->files); trace_probe_set_flag(tp, TP_FLAG_TRACE); return 0;}
struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp, struct trace_event_file *file){ struct event_file_link *link;
trace_probe_for_each_link(link, tp) { if (link->file == file) return link; }
return NULL;}
int trace_probe_remove_file(struct trace_probe *tp, struct trace_event_file *file){ struct event_file_link *link;
link = trace_probe_get_file_link(tp, file); if (!link) return -ENOENT;
list_del_rcu(&link->list); kvfree_rcu_mightsleep(link);
if (list_empty(&tp->event->files)) trace_probe_clear_flag(tp, TP_FLAG_TRACE);
return 0;}
/* * Return the smallest index of different type argument (start from 1). * If all argument types and name are same, return 0. */int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b){ int i;
/* In case of more arguments */ if (a->nr_args < b->nr_args) return a->nr_args + 1; if (a->nr_args > b->nr_args) return b->nr_args + 1;
for (i = 0; i < a->nr_args; i++) { if ((b->nr_args <= i) || ((a->args[i].type != b->args[i].type) || (a->args[i].count != b->args[i].count) || strcmp(a->args[i].name, b->args[i].name))) return i + 1; }
return 0;}
bool trace_probe_match_command_args(struct trace_probe *tp, int argc, const char **argv){ int i;
if (tp->nr_args < argc) return false;
for (i = 0; i < argc; i++) { int len = strlen(tp->args[i].name);
if (strncmp(argv[i], tp->args[i].name, len) || argv[i][len] != '=' || strcmp(argv[i] + len + 1, tp->args[i].comm)) return false; } return true;}
int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **)){ int argc = 0, ret = 0; char **argv;
argv = argv_split(GFP_KERNEL, raw_command, &argc); if (!argv) return -ENOMEM;
if (argc) ret = createfn(argc, (const char **)argv);
argv_free(argv);
return ret;}
int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args, u8 *data, void *field){ void *p; int i, j;
for (i = 0; i < nr_args; i++) { struct probe_arg *a = args + i;
trace_seq_printf(s, " %s=", a->name); if (likely(!a->count)) { if (!a->type->print(s, data + a->offset, field)) return -ENOMEM; continue; } trace_seq_putc(s, '{'); p = data + a->offset; for (j = 0; j < a->count; j++) { if (!a->type->print(s, p, field)) return -ENOMEM; trace_seq_putc(s, j == a->count - 1 ? '}' : ','); p += a->type->size; } } return 0;}